1. Field of the Invention
The present invention relates to a device for control of a robot manipulator for a metal sheet bending installation.
2. Description of the Prior Art
The present invention is advantageously applied to the command and control of a robot manipulator of the type described in Italian Patent application filed Mar. 15, 1988 under application No 67224-A/88 by the same applicant. This manipulator device comprises a pair of motor driven manipulator heads which translate within a manipulation space and are rotatable about a common axis which is parallel to a linear bending zone defined by the dies of a press. The manipulator heads are adapted to grip the opposite edges of a metal sheet and to position this metal sheet between the dies of the press in such a way as to allow a predetermined bending of the metal sheet. This manipulator device further has an arm with a plurality of auxiliary pincers which can grip an edge of the metal sheet to invert it. The manipulator device and the press are controlled by an electronic command and control unit which, on the basis of previously memorised instructions, imparts thereto sequential instructions defining successive bending cycles.
The instructions for the various working phases are normally imparted to the command unit by the so-called "self-learning" procedure on the basis of which an operator physically moves the machine in a sequential manner through the movements which the bending cycle requires, and when each individual movement has been effected inserts into the command unit the parameters relating to this movement.
In this way the various positions assumed by the elements of the machine (for example the successive positions assumed by the manipulator heads) are memorised in a sequential manner within the RAM memory of the command and control unit, and can subsequently be read by this command unit and therefore performed again during the operating bending cycles.
It is clear from what has been explained above that when it is desired to modify a previously memorised bending cycle it is necessary to perform a new self-learning procedure which takes up considerable time to complete and is rather onerous.
Moreover, the staff employed to perform the self-learning procedure must know the machine and the admissible sequence of operating steps very well, and must position the various elements thereof with extreme precision, so as to insert reliable data into the control unit.